Summary: The impacts of international migration on development in the sending countries, and especially the effects on remaining household members, are increasingly studied. However, comparisons of households in developing countries with and without migrants are complicated by a double-selectivity problem: households self-select into migration, and among households involved in migration, some send a subset of members with the rest remaining while other households migrate en masse. The authors address these selectivity issues using the randomization provided by an immigration ballot under the Pacific Access Category of New Zealands immigration policy. They survey applicants to the 2002-05 ballots in Tonga and compare outcomes for the remaining household members of emigrants with those for members of similar households that were unsuccessful in the ballots. The immigration laws determine which household members can accompany the principal migrant, providing an instrument to address the second selectivity issue. Using this natural experiment, the authors examine the myriad impacts that migration has on remaining household members, focussing on labor supply, income, durable assets, financial service usage, diet, and physical and mental health. The analysis uses multiple hypothesis testing procedures to examine which impacts are robust. The findings indicate that the overall impact on households left behind is largely negative. The findings also reveal evidence that both sources of selectivity matter, leading studies that fail to adequately address them to misrepresent the impact of migration.